Radio signals in a wireless communication network may propagate directly from a transmitter to a receiver along a line of sight, or may be reflected by one or more objects before it is received by the receiver. In a typical indoor Wi-Fi network, for example, a signal transmitted from an access point to a mobile device or vice versa may be reflected by various obstacles, for example, walls, beams, furniture, appliances, or any surfaces that reflect radio waves. In a longer-range wireless network such as a cellular network, for example, a signal transmitted from a base station to a mobile device or vice versa may be reflected by various buildings, structures, pavements, hills or mountains, for example.
In various types of wireless communication networks, it is often desirable to obtain time-of-flight measurements between transmitters and receivers, for example, for determining relative distances or ranges between such devices which may be useful for positioning, navigation, or other uses. As such, it may be desirable to measure the shortest time of flight between a transmitter and a receiver, that is, the time of signal propagation through a line of sight. However, due to multiple reflections in typical indoor or outdoor environments, the signal received by the receiver may in effect represent a superposition of signals from multiple paths of propagation. Therefore, it may be useful to able to distinguish the shortest time of flight from longer times of flight due to reflections, multipath effects, or other effects.